[gurpswoo1]

If it's made of pine then that serious trouble. The water has already been drained from the wood and if it's splitting now it means they didn't seal the ends with wax and let it drain correctly.

Your best bet is to seal the ends with Wax or even certain greases (not recommended to use grease, it's not good stuff) like mosavon said.

Make sure you keep it away from from any heat sourse, even small ones over time will remove moisture from the wood and cause it to shrink, the result will be a bent lid.

If it was me I would place several bags around it which will preserve the the moisture inside due to condensations.